Speedometer



1935- Y c. STOECKLIN 1,992,252

SPEEDOMETER Filed Jan. 9, 1929 2 Sheets- Sheet 2 Patented Feb. 26, 1935UNITED STATES SPEEDOMETER Charles Stoecklin, Paris, France, assignor toSociete Anonyme Tel, Paris, France Application January 9, 1929, SerialNo. 331,866

5 Claims.

This invention relates to speedometers of the known periodic-countertype which include in their construction a drive shaft, an oscillativelymounted pinion which may be carried by a rocking lever adapted to bedriven by the said drive shaft, two gear trains symmetrically disposedwith respect to the said pinion, a central indicating shaft common tothe gear trains and adapted to control the movements of an indicatingpointer or other equivalent part, a horological movement for driving camor equivalent means to periodically produce engagement and disengagementof the pinion alternately with the two gear trains and for stopping andreleasing the said gear trains.

With such devices as hitherto constructed, the horological movementdrives a shaft carrying one cam for causing engagement and disengagementof the pinion with the gear trains, and another cam for operatingmechanism to cause the stopping and releasing of the said gear trains.

According to the present invention, in speedometers of the type to whichthe invention relates, a single cam element, which may be in the form ofan eccentric or otherwise, is provided for producing engagement anddisengagement of the pinion alternately with the two gear trains andalso for stopping and releasing the said gear trains.

Apparatus constructed according to the invention differs from apparatusof the known type consequently in that its mechanism is considerablysimplified. Moreover, it permits of the use of robust elements for givenoverall dimensions and cheapens the cost of manufacture and upkeen.

My invention will be more readily understood by those skilled in the artwith reference to the accompanying drawings forming part of thisspecification and in which- 'Fig. 1 is a front view of my device withthe front dial-carrying plate removed;

Fig. 2 is a sectional view taken on a line passing through the axes A,B, and C;

Fig. 3 is another sectional view as seen from below and takensubstantially on the horizontal line passing through the axis D;

Figs. 4 and 5 are detail views of a modified form of mechanism;

Fig. 6 is a sectional view through another modified form of mechanism;and

Fig. 7 is a detail of a stop device thereof.

Referring to the drawings more in detail, a shaft 1, controlled directlyor indirectly by the vehicle or other member whose speed is to bemeasured, transmits its movement through the medium of a pinion 2 rigidwith shaft 1 to a toothed wheel 3. A pinion 4 is mounted on the sameshaft 36 with the toothed wheel 3, and is adapted to rock from left toright in a manner well known in the art under the action of an arm 27,for periodically driving the wheels 5 or 22, the arm 2'7 beingcontrolled, for example, through the medium of an eccentric 28, adaptedto become displaced in a slot 38 (Fig. 1). The eccentric 28 turns aboutthe shaft D by any suitable means and in particular may be tributary toa horological movement shown diagrammatically in Fig. 3 and including afriction barrel 33, an escapement wheel 35 and a balance wheel 34. Thesaid eccentric acts directly on the arm 27 and consequently on thepinion 4 as well as on pawls 29 and 30 respectively subjected to theaction of springs 31 and 32.

It will be noted that this well-known oscillating movement imparted bythe arm 27 moves the shaft 7 36 to the right or to the left upon whichshaft are mounted the wheels 3 and 4.

The indicating gear train shown on the left hand side of Fig. 2comprises a wheel 22 adapted to be driven from the pinion 4, through therequired angular distance and against the action of a spring 23. Thewheel 22 carries a pin 18 on its surface, which is adapted to contactwith a stop pin 79 fixed to the framework, to limit the return movementdue to the action of the spring. Coaxial with but free to turnindependently of the wheel 22, is a toothed wheel 15 having a projectingpin 17, with which the projection 18 of the wheel 22 is adapted toco-act. 16 is a return spring normally for keeping the pin 1'7 pressedinto contact with the projection 18, the spring 16 being fixed on theone hand to the arbor of the wheel 15 and on the other hand to theframework. When the wheel 22 is driven by the pinion 4, consequently theprojection 18 carries round with it the pin 1'7 and consequently turnsthe wheel 15 against the action of its return spring 16. The pawlco-operates under the action of the eccentric 28 with the wheel 15.

The indicating gear train on the right hand side of Fig. 2 comprisesparts corresponding exactly with those on the left hand side. In thisright hand train the wheel 5 which is adapted to be driven from thepinion 4 has a controlling return spring 6, and a projection 20 from thesurface thereof adapted to come against a stop 21 fixed to theframework. 7 is the wheel coaxial with the wheel 5 but free to turnindependently there'- of, the wheel '7 having a pin 19 with which theprojection 20 co-acts, and a return spring 40. The pawl 29 controlled bythe eccentric 28 co operates with the wheel 7.

10 is a spindle carried in suitable bearings in the framework and havingthe indicator hand 39 fixed thereto. This spindle 10 has fixed theretoso as to turn therewith a projection or arm 11, and the spindle hasmounted to freely turn thereon two wheels 8 and 14. The wheel 15 of theleft hand gear train meshes with the wheel 14 and the wheel 7 of theright hand gear train meshes with the wheel 8. 9 is a spring attached tothe framework on the one hand and on the other hand to the spindle 10,the action of the spring tending always to return the hand 39 to zero.

12 is a pin projecting from the wheel 8 and coming in the path of thearm or catch 11, and 13 is a corresponding pin projecting from the wheel14 and also coming into the path of the arm or catch 11.

With the above construction, it follows that by the action of theeccentric 28 the pinion 4 for a precise period of time drives the wheel5, during which time the setting of the parts is such that the pawl 30holds the wheel 15 from return movement under the action or its spring16, whilst the pawl 29 is freed from the wheel 7, allowing it to beturned by the action of the projection 20 on the pin 19, and then alsoby the action of the eccentric 28, for another precisely similar periodof time, the pinion t is freed from the wheel 5 and brought intoengagement with the wheel 22 and simultaneously the pawl 29 caused tohold the wheel 7 from movement whilst the pawl 30 frees the wheel 15,this action continuing, so that by the timed movements of the eccentric28 the pinion 4 is alternately engaged with the wheel 5 and the wheel22.

When the pinion 4 is in driving engagement with the wheel 5, it causesthe projection 20 to be moved from the stop 21 and the spring 6 to beadditionally stressed. The projection 20 engages the pin 19 and turnsthe wheel 7 (the pawl 29 being free). The turning of the wheel 7additionally stresses the spring 40. The wheel 7 turns the wheel 8 andcauses its pin or projection 12 to carry round with it the catch or arm11, thus turning the spindle 10 and additionally stressing the spring 9.The spindle 10 carries round with it the indicating pointer 39. When thepinion 4 leaves the wheel 5 and comes into engagement with the wheel 22,the following actions take place, those of the gear train on the righthand side of Fig. 2 being first considered.

Immediately the wheel 5 is freed from the pin ion 4, it is then onlyunder the control of the spring 6, and by the stress of this spring, itis turned back until its projection 20 contacts with the stop 21,bringing the wheel 5 to rest. By this action the projection 20 has leftthe pin 19, but as the wheel 7 is now held by the pawl 29, this wheelcannot turn backwards under the action of the spring 40. Consequent uponthis, the wheel 8 cannot turn back but its pin 12 continues to hold theprojection or catch 11 against the returning stress of the spring 9 onthe spindle 10, and thus the indicator 39 remains in the set position.

By the pinion 4 meshing with the wheel 22, and simultaneously the pawl29 being engaged with the wheel 7 and the pawl 30 freed from the wheel15, the wheel 22 is driven so that it imparts additional stress to thespring 23. Simultaneously the projection 18 carries round with it thepin 17 of the wheel 15 and turns this wheel 15, imparting additionalstress to its return spring 16. The

turning of the wheel 15 turns the wheel 14 so that its pin 13 movestowards the new position of the catch or projection 11. If during thissecond period, the speed of the shaft 1 has increased, then the amountby which the wheel 22 is turned will be greater than the amount by whichthe wheel 5 had previousiy been turned, and consequently the pin 13 willmove through a greater angular distance than that previously movedthrough by the pin 12. It will then contact with the arm or projection11 and carry this arm or projection round through a greater angulardistance, and correspondingly turn the spindle 19 and increase the ofthe spring 9 and also increase the reading of the pointer 39.

If on the other hand the shaft 1 turns to a less extent during thissecond period than the first period, then the pin 13 will not attain thearm or projection 11, whilst should the speed of the shaft 1 remainconstant, the pin 13 will just reach the arm or projection 11.

When the pinion 4. is freed of the wheel 22 and brought into engagementwith the wheel 5, the pawl 30 is brought into engagement with the wheel15 and the pawl 29 freed of the wheel 7.

The immediate consequences of this action are that the wheel 22 nowbeing only controlled by the spring 23 is turned so that its projection18 is brought back to the stop 79 and as now the wheel 7 is freed fromthe pawl 29, it is only controlled by its spring 40, and consequentlyturns so that its pin 19 moves towards the projection 20 of the wheel 5,which projection 20 is moving towards the pin 19 by the new driveimparted thereto.

By the return movement of the wheel 7, through the meshing oi? thiswheel with the wheel 8, the pin 12 has been removed from its previouslyset position, and if in this position it was holding the catch orprojection 11 in position (that is if the other pin 13 had not movedthrough the same or a greater angular extent than the pin 12) then bythe movement of the pin 12 from the catch or projection 11, the saidcatch or projection 11 is freed, and the spindle 10 can be turned backby the return spring 9, until the catch or projection 11 comes againstthe pin 13, which limits the return movement.

In this manner the position of the spindle 10,

and consequently of the needle carried thereby,

indicates the speed.

The relative positions of the detents 29 and 30, the wheels 4, 7 and 15,and the eccentric 28, are to a certain extent shown diagrammatically inFig. 1, and it should be realized that before the pinion 4 comes out ofmesh with either of the wheels 7 or 15, the corresponding detent 29 or30 comes into engagement with the said wheel to prevent it running backunder the action of its controlling spring, and similarly, the detent isremoved from the wheel 7 or 15, as the case may be, immediately afterthe said wheel has been engaged by the pinion 4.

It should also be pointed out that equivalent parts in modified forms tobe described operate in a similar manner.

Referring to Fig. 4, which shows another modification the control of themeasuring pinion 4 mounted on the extremity of arbor 36 and drivingalternately and periodically the wheels 5 and 22 is effected by means ofa bell crank lever 41, the extremity of one of the arms thereof carryingthe said pinion 4 loosely mounted thereon. The said bell crank leverturns about a pivot 42 and the other arm which is shaped in a way toform a spring along the part 44 thereof is provided with a. ratchet 43bearing on a cam 45 driven by a time movement. Said cam 45 carries onits periphery three projections 46 and three notches 47 against whichthe ratchet 43 is drawn by a spring 48, the whole being arranged in away that in accordance with the periphery of cam 43 the pinion 4 isactuated through three oscillations per revolution, that is, threeengagements for meshing with the wheel 5 and three other engagements formeshing with the wheel 22.

The stopping and liberation of wheels '7 and 15 is effected by a doubleleaf spring 50 rigid with lever 41 (Figs. 4 and 5) or on arm 27 (Fig. 1)but movable with them.

The springy part 44 of the bell crank lever 41 has for a purpose toprevent the production of faulty meshing of pinion 4 with the toothedwheels 5 and 22. In fact if the bell crank lever 41 were rigid therecould take place an error in the measurement of the instrument in thecase where the teeth would strike each other instead of penetrating eachother. The spring allows slight flexing which permits driving of thegears as soon as the teeth come into engagement.

In order to overcome the above indicated inconvenience, I may in certaincases mount the shaft 36 as shown in Fig. 5, that is, in a throat whichserves as a bearing for pinion 4 upon which bears a leaf spring 49allowing slight play of the shaft 36, which play serves the purpose offacilitating meshing of toothed wheels 5 and 22.

On the other hand the part 44 of the lever 41 could thus act directly onthe heel of pawls 29 and 30 (Fig. 1) instead of carrying the fiat spring50 shown in Fig. 4.

The oscillation of the pinion 4 directly, from one wheel to another in away that it is consecutively and alternatively in engagement with thewheel 5 and the wheel 22, has the following characteristics:

First-Each of said engagements, that is, in each direction andsymmetrically, is accompanied by the four actions simultaneously, abovenoted, and all in the same measuring time of the device, and identicalfor each of these four actions, to wit, engagement, disengagement,stopping and liberation.

Therefore each engagement simultaneously establishes and breaks themeshing of the two groups of wheels.

Second.--Only a single time distributing member in the form of a singlecam (Fig. 4), an eccentric (Fig. l) or the equivalent thereof isnecessitated.

Third-It is possible to specially dispose the direction lever of pinion4 in a way that it can yield when the teeth of said pinion 4 meet thoseof the wheels'5 or 22 or normally mesh with such teeth.

Figure 6 illustrates another embodiment of my device. The variable speedto be measured is transmitted, for example, to the main shaft 74 and towhat may be termed the pinion element, equivalent to the pinion 4 andconstituted in this case by a two-face clutch member 61 loosely keyedthereon, the transmission being effected by means of pinions 56 and 57.On the other hand, the shaft 52 which carries the cam 51 has impartedthereto, when the apparatus is in motion, a constant movement regulatedby a horological movement, in a way that during the first measuringtime, the lever 58 which is pivoted liberates the ratchetwheel 65, andthe lug '73 stops the ratchet wheel 65' in the position where it happensto be and the double wheel 61 liberates the wheel 62'. The return spring53 is adapted to constantly cause the end of lever 58 to bear against acam 51 carried by a shaft 52. Springs 68 and 68' return the wheels 65and 65' to their initial positions. The springs 67 and 67' return thewheels 62 and 62 to their initial position and finally the spring '75tends to return the pointer 71 and the member 63 to the zero positionwhen not retained by the lugs 64 and 64 of the wheels 65 and 65.

Fig. 7 illustrates another method of stopping the wheel 65 representingwheels 65 and 65' of Fig. 6. In this case a spring arm '72 is providedwhich carries at each extremity a pinion '73 of which the teeth areadapted to be engaged at the desired moment with the teeth of thecorresponding wheel 65 or 65, this pinion being mounted on a spindle insuch a way that it can rotate slightly so that the teeth thereof cancome into engagement with the teeth of the wheel 65 or 65' even if theteethin the two wheels to be engaged come opposite one another in thefirst place. The pinion '73 being only adapted'for a limited amount ofrotational movement on its supporting spindle serves, after engagementwith the teeth of the wheels 65 and 65, to stop the rotation of suchwheels.

While I have described what I deem to be the preferable forms of mydevice I do not Wish to be limited thereto as there might be changesmade in the forms of construction and dispostion of parts withoutdeparting from the invention as comprehended within the scope of theappended claims.

Having described my invention what I claim as new and desire to secureby Letters Patent is:

l. A speedometer of the type described comprising in combination a driveshaft, a pinion element formed as a double toothed wheel and looselykeyed to said drive shaft, a pair of toothed wheels with which the saiddouble toothed wheel is adapted to co-operate, a ratchet wheelassociated with each of said pair of toothed Wheels, an indicating geartrain, means for driving said indicating gear train from the movementsof the ratchet wheel, a single cam element, a horological movement fordriving said single cam element, a lever element, one of the arms ofwhich engages with the double toothed pinion element and the other ofwhich is in operative engagement with the single cam element to impartan oscillating movement to the lever, thereby engaging the said pinionelement periodically and alternately with the two co-operating toothedwheels, a double leaf spring carried by and moving with the said leverelement, and detents carried at the ends of said double leaf spring forengagement with and disengagement from the said two ratchet wheels.

2. A speedometer of the type described comprising in combination a driveshaft, a pinion element formed as a double toothed wheel and looselykeyed to said drive shaft, a pair of toothed wheels with which the saiddouble toothed wheel is adapted to co-operate, a ratchet wheelassociated with each of said pair of toothed wheels, an indicating geartrain, lugs on each of said ratchet wheels, a stirrup member adapted tobe engaged by said lugs and transmitting its movement to the indicatinggear train, a single cam element, a horological movement for drivingsingle cam element, a lever element, one of the arms of which engageswith the double toothed pinion element and the other of which inoperative engagement with the single cam element to impart anoscillating movement to the lever, thereby engaging the said pinionelement periodically and alternately with the two co-operating toothedwheels, 9. double leaf spring carried by and moving with the said leverelement, and detents carried at the ends of said double leaf spring forengagement with and disengagement from the said two ratchet wheels.

3. A speedometer of the type described comprising in combination a driveshaft, a pinion element formed as a double toothed wheel and looselykeyed to said drive shaft, a pair of toothed wheels with which the saiddouble toothed wheel is adapted to co-operate, a ratchet wheelassociated with each of said pair of toothed wheels, a pin on each ofsaid pair of toothed wheels for engaging with a co-opcrating abutmentprovided on each of the said ratchet wheels, an indicating gear train,lugs on each of said ratchet wheels, a stirrup member adapted to beengaged by said lugs and transmitting its movement to the indicatinggear train, a single cam element, a horological movement for drivingsaid single cam element, a lever element, one of the arms of whichengages with the double toothed pinion element and the other of which isin operative engagement with the single cam element to impart anoscillating movement to the lever, thereby engaging the said pinionelement periodically and alternately with the two co-operating toothedwheels, a double leaf spring carried by and moving with the said leverelement, and detents carried at the ends of said double leaf spring forengagement with and disengagement from the said two ratchet wheels.

4. A speedometer of the type described comprising in combination a driveshaft, a pinion element formed as a double toothed wheel and looselykeyed to said drive shaft, a pair of toothed wheels with which the saiddouble toothed wheel is adapted to co-operate, a ratchet wheelassociated with each of said pair of toothed wheels, a pin on each ofsaid pair of toothed Wheels for engaging with a co-operating abutmentprovided on each of the said ratchet wheels, an indicating gear train,lugs on each of said ratchet wheels, a stirrup member adapted to beengaged by said lugs and transmitting its movement to the indicatinggear train, a single cam element, a horological movement for drivingsaid single cam element, a lever element, one of the arms of whichengages with the double toothed pinion element and the other of which isin operative engagement with the single cam element to impart anoscillating movement to the lever, thereby engaging the said pinionelement periodically and alternately with the two co-operating toothedwheels, a double leaf spring carried by and moving with the said leverelement, and a friction pinion carried at each end of said double leafspring for engaging with and disengaging from the said two ratchetwheels.

5. A speedometer of the type described comprising in combination a driveshaft, a pinion element formed as a double toothed wheel and looselykeyed to said drive shaft, a pair of toothed wheels with which the saiddouble toothed wheel is adapted to co-operate, a ratchet wheelassociated with each of said pair of toothed a p-n on each of pair oftoothed wheels for engaging with a oo-operating abutment provided oneach of the said ratchet wheels, an indicating gear train, lugs on eachof said ratchet wheels, a stirrup member adapted to be engaged by saidlugs and transmitting its movement to the indicating train, a single camelement, a horological movement for driving said single cam element, alever element, one of the arms of which engages with the double toothedpinion element and the other of which is in operative engagement withthe single cam element to impart an oscillating movement to the lever,thereby engaging the said pinion element periodically and alternatelywith the two co-operating toothed wheels, a double leaf spring carriedby and moving with the said lever element, detents carried at the endsof said double leaf spring for ongagement with and disengagement fromthe said two ratchet wheels, spring means for returning the said pair oftoothed wheels to their initial position, further spring means forreturning the ratchet wheels to their initial position, further springmeans for returning the indicating gear train to its initial positionand spring means for maintaining the end of the lover element inconstant engagement with the single cam element.

CHARLES STOECKLIN.

